Hydraulic Landing Gear Uneven.

[oscar]

Greetings,

Seems the left leg of our hydraulic landing gear is not as powerful as the right one. The left front side of the coach is always a little down from the right, and it seems to get worse over time....(days). Is there now a way to operate one and not the other?

I'm thinking of putting shutoff valves in both legs so I can operate them individually to level/adjust the front end.

Has anyone done this?

 

[danemayer]

Hi Oscar,

There was a recent thread on this. I assume you have hydraulic front landing jacks, NOT the auto-leveling system.

With front landing jacks, you level the coach left-to-right at the wheels. The front jacks lift to level front-to-rear. They have a single valve feeding both jacks. So the jack with less resistance will move first, then both will move. If the rear of the coach is not level left-to-right, the front will not be level either.

In addition, the weight of slideouts is not the same on each side. So when extended, it may change the leveling a bit at the back as the suspension gets loaded by slide out weight. The front will follow. Some people put an extra inch or two of support under the heavy side so that when it settles with slides out, it's level at the rear (and front).

It's possible, but less likely that you could have a problem with the landing jacks.

If you find a level parking lot, and have a long carpenter's level, you can check the level at the rear while hitched to the truck. Check with slides in and with slides out. That'll give you a baseline with the front landing gear out of the equation. Then unhitch and recheck leveling at front and rear, with slides in and out.

If there's a problem with the front jacks, you'll be able to describe the circumstances in detail to the service tech so he can replicate the problem.

Now if you actually have auto-leveling, the jacks probably each probably have a separate valve and you may have a completely different situation.

 

[oscar]

Yes, I am familiar with the leaning after slide deployment effect. Our old camper had one long slide on one side and I definitely had to pre-load it left side up. I guess the fact that I have slides on both sides now threw me off. I figured the fridge and stove would offset the couch, but fact is that the left side slide is a lot larger, plus there's the bedroom. Not a lot in and of itself, but it all adds up.

Still, I'm more level over the wheels than I am over the landing gear. There is some twisting going on, and right now I think it's the landing gear. I could be wrong. After looking at the plumbing today I see where the pressure goes into the right side, flows through and then to the left side. No way to isolate the right side.

 

[oscar]

OK, because I can't stand it and have to do something, and rather than hooking up and moving the thing (long story with a slide out over a spigot post etc etc) I got the bottle jack out and one by one put the three left wheels on a 2" (not "2 by" a true 2" board) Only took 10 minutes and now we're much much better.

And, in the process discovered another interesting tidbit. I use a bubble level on the kitchen counter, the ledge under the tv and the counter in the forward bathroom. Well, guess what. Depending on WHERE you put the thing on said counters you can get different results......

It's good enough now. I need to have a beer and start worrying about something else.........

 

[slaytop]

I'm probably a bit late to respond to this thread, but I think the uneven weight distribution from one side to the other causes the frame to twist as the landing gear raises the front of the unit. Since the landing gear hydraulics are plumbed to have an even pressure on both sides, the leg of the lighter side will push up first until the resistance matches the heavier side. The frame will be pushed up on the lighter side and, being flexible (not entirely rigid), will cause it to twist until the resistance is the same on both legs.

I can't say how this will affect the frame over time but my suspicion is it could place a permanent twist and also may lead to the failure of a frame component or weld. I see the same process occuring when I raise my unit and when I park it for a period of time I try to set the front landing gear on blocks in its fully retracted position so the tires and landing gear are on the same level.

 

[oscar]

Yes, I am wondering about twisting too.......

 

[danemayer]

If fluid is free to flow between left and right jacks in front, then if something changes at the back, the front will follow because nothing keeps the fluid from flowing from one side to the other. Twisting the frame would assume that the back moves left-to-right and the front doesn't.

 

[Hastey]

If fluid is free to flow between left and right jacks in front, then if something changes at the back, the front will follow because nothing keeps the fluid from flowing from one side to the other. Twisting the frame would assume that the back moves left-to-right and the front doesn't.

I concur with Danny. The frame has too much weight and is too long to lift independently with the landing legs. Big chance to tweak the frame. My first guess is that you've got fluid getting past the packing on the ram or a check valve that is not closing. Does it constantly back off or just some and stop?

 

[oscar]

It seems to stop after it settles a bit. And, it seems to be less now that I've cranked up the ODS a little. It could all be an optical delusion on my part. Right now I am walking around inside and not noticing anything. Again, after I discovered that putting the bubble level in different places on the counter surfaces yielded wildly varying results I started looking a little harder and again it appears to be less of an issue now. For now I'm happy and will let it lie.


I do want to pursue a hydraulic left right adjustment but will start a separate thread on that.